The present invention relates to an improved contact body for use in a liquid and gas contact apparatus and, in particular, to a contact body formed of alternating corrugated sheets of material wherein the corrugations in adjacent sheets are positioned at an angle to each other.
Contact bodies or packings for gas and liquid contact apparatus have been previously proposed in which the contact body is formed of adjacent corrugated sheets of material. Corrugated sheets are placed adjacent one another with their ridges or crests contacting each other so that channels or passageways are formed between the sheets to provide continuously varying width passages in the sheets which result in the flow direction of the gas and liquid being repeatedly changed during passage through the body. It has been found that contact bodies of this type are highly efficient in operation. Once such contact body is shown in U.S. Pat. No. 3,262,682.
An improvement of the basic contact body shown in Bredberg U.S. Pat. No. 3,262,682 was developed and disclosed in U.S. Pat. No. 3,792,841 to Munters. According to that patent a contact body of the cross-flute type for use in cross-flow cooling towers, or the like, was constructed such that the angles of inclination between the folds of the corrugations in adjacent sheets were varied to obtain optimum exchange between the fluids. In particular, the corrugations of one set of sheets are arranged to cross the corrugations of the adjacent second set of sheets at acute angles in the range of 20.degree. to 80.degree.. The corrugations of the first set of sheets described in that Munters' patent are arranged to have a greater inclination to the horizontal plane of the contact body than the corrugations of the second set of sheets, with the corrugations in the first set of sheets being inclined upwardly in the direction of gas flow. This arrangement produces a bisector angle of the corrugations of the respective sheets which inclined downwardly opposite to the direction of gas flow thereby to counteract the undesirable lateral displacement of liquid caused by the gas flow with the result that liquid is distributed uniformly over the sheets. This Munters' type pack or contact body has been highly successful in use and generally accepted as a cooling tower medium and in evaporative air cooling applications.
The use of unequal angles in adjacent corrugated sheets as described in the Munters' patent directs more water to the air-entering side of the contact body. This produces two advantages. First, it directs more water to the entry side of the media where dirt and deposits occur. Secondly, it prevents the liquid from becoming entrained in the airstream at velocities of less than 800 feet per minute and water loadings of less than 1.5 gallons per minute per square foot of top surface area of the contact body.
In evaporative coolers and humidifiers in which the Munters' type of contact body has normally been used, a water recirculating system is typically provided. In such systems a certain amount of water is normally bled off from the system when the water becomes concentrated with contaminants due to evaporation. Then a makeup source of water provides fresh water to makeup for evaporation and bleed-off. However, due to water restrictions and lack of maintenance, it has been found that bleed-off may not be adequate to keep the contact body media clean, even with the Munters' construction. As a result, the openings, particularly on the air inlet side of the contact body, slowly become plugged enough to seriously restrict air flow. One solution to this problem has been to provide contact bodies with relatively large amplitude heights in corrugations in order to increase the size of the passageways. However, this results in a reduction of the available evaporative surface and considerably less cooling.